HDSDR_IF-Offset_How to Set?

Discussion in 'Software Defined Radio (SDR)' started by VA7TA, Jan 26, 2020.

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  1. VA7TA

    VA7TA Ham Member QRZ Page

    Greetings All,

    I am using a FunCube Pro SDR dongle as an IF receiver front end for HDSDR which provides very nice pan adapter serial port control via OmniRig for my TS-870S.

    However I find I do not have freedom to set the HDSDR IF-LO offset. It seems the IF-LO offset is fixed to the HDSDR front-end ~mode~ offsets which for USB is only about 1.5KHz. This creates a null in the audio spectrum at the LO frequency. I noticed some online HDSDR screen views that show the IF-LO offset around 10 KHz which would be out of the audio passband which would be much better. Setting the Global offset doesn't seem to change the IF offset value. I have the "set LO<->Tune Offset" setting set to 10000Hz but it doesn't have any affect as it appears disabled since there is no tick mark beside it. If I click on it a window pops up with my 10000 Hz entry but when I click the "OK " button and then go back it still shows the "set LO<->Tune Offset" as NOT selected, ie no check mark beside it. I wonder if there is an OmniRig or HDSDR setting that I have missed?

    I wonder if someone in this group can help me out with this?

  2. VA7TA

    VA7TA Ham Member QRZ Page

    Greetings Again,

    Turns out "Global Offset" works for me now for setting the IF offset. Mysteriously when I tried it several times before it didn't work.

    Happy Ending!
    Tom, VA7TA
    N3AWS likes this.
  3. VA7TA

    VA7TA Ham Member QRZ Page


    I am back again still stuck with this issue. It turns out the "Global Offset" which provided the 10 KHz IF offset I was looking for also offset offset my mouse click tuning by 10 KHz. I think I need OmniRig to correct the data sent to my TS-870S by 10000 Hz. I have tried setting the "Misc Options>set LO <-> Offset" to 10000 but it does not seem to have any effect - I have tried 0, 10000 and -10000 settings and nothing seems to change. It is as if this setting is not working.

    Any suggestions?

    Still in Need of Happy Ending, :(!
  4. VA7TA

    VA7TA Ham Member QRZ Page

    I keep answering my own posts. I finally have it working the way I want.

    My rig IF frequency center is 8,830,155 Hz. I found I needed to add 10KHz to the IF frequency in the HDSDR RF Front End settings to 8840155 Hz. The 10000 Hz Global Offset now compensates for the IF frequency shifted specification. This results in an HDSDR LO offset of about 10KHz +/- mode offsets which shifts the LO frequency notch away from the audio passband. The HDSDR display now tracks my TS-870S properly.

    I think I finally have found a happy ending now after numerous hours of effort, ;).


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